Managing the efficient traffic flow over the nation's roadways is an extremely complex problem. In several metropolitan areas, roadways have reached, and even exceeded, their capacities further complicating the problem. One area that is particularly difficult to manage is the merging of two or more lanes of traffic into a single lane. This can occur for a variety of reasons including roadway maintenance/construction that requires unfettered access to a lane of traffic thereby requiring closure of the lane, or the design of the roadway is such that one lane is required to merge with another, a feature that is very common with roadway on-ramps.
Traffic flow in these merge zones frequently gets congested and backed up as drivers in two or more adjacent lanes maneuver their vehicles to squeeze into a single merging lane. Bottlenecks occur particularly when traffic density is high. This can result in traffic getting backed up upstream of the merge zone causing delays and increasing the potential for collisions. A cause for this traffic congestion and slowdown is the “me-first” psychology of drivers. Generally speaking, drivers are unwilling to allow their neighbors in the adjacent lane to merge into their lane by appropriately adjusting their vehicle speed to open up a large enough gap to allow the merge to occur smoothly
Several methods exist to address the problems inherent in merge zones. For example, there are several systems employing smart or intelligent automobiles. The basic premise of all these systems is that the automobile of the future will be equipped with a device that will allow it to communicate with other automobiles in its vicinity on the roadway. Such automobiles will then be able to operate in a cooperative manner by communicating with each other and thereby allowing maximum safe throughput of vehicles on the roadway. Examples of this type of systems are disclosed in United States Patent Application numbers 2004/0260455, 2004/0068393 and 2005/0137783. The significant shortcoming to these systems is that they require all vehicles to be equipped with special devices. Not only will this take several years to implement, it may be impossible to economically retrofit older vehicles. This may be especially true in areas with a hospitable climate, such as southern California, where there are large populations of well-maintained antique and vintage vehicles.
U.S. Pat. No. 6,559,774 discloses a work zone safety system and method. The system is adapted to selectively flash a suitable warning, e.g., “DO NOT PASS” or “MERGE LEFT” or “MERGE RIGHT.” A significant shortcoming to this system is that it fails to provide the motorist with any guidance on the proper speed they should attain for a safe and efficient lane merge.
U.S. Pat. No. 6,825,778 discloses a variable speed limit system for use in work zones. The system includes at least two spaced-apart stations, where each station includes a plurality of sensors to gather information. The station includes a controller which is programmed to analyze data which is received from the sensors and to derive an optimum speed limit at a selected location adjacent the work zone. The station then displays to the motorist through a message board the optimum speed. A significant shortcoming of this system is that it is difficult for a motorist to read the message board and maneuver their vehicle to the optimum speed, while simultaneously attempting to safely merge. Also, several motorists may have a speedometer that is either not working or is severely mis-calibrated, such that attempting to implement the speed shown on the message board would be a futile, if not dangerous task.
What is needed therefore is a traffic control system that provides motorists with simple and effective guidance regarding the proper speed needed to achieve a safe and efficient lane merge. Moreover, the system should not require any special equipment on any vehicle, such that the system may be implemented immediately.